Using Consultation Call to Transfer Call Across Endpoints

ABSTRACT

A method for transferring a telephone call from a client computer to a second electronic device includes establishing a connection for a telephone call between the client computer and a first electronic device, and sending a request to a server computer to transfer the telephone call from the client computer to the second electronic device, the client computer and the second electronic device having the same user, the request initiating a consultation call to the second electronic device. The method also includes receiving a response from the server computer that the second electronic device has accepted the telephone call, and replacing the client computer with the second electronic device as a party in the telephone call with the first electronic device, the continuity of the telephone call being maintained at the first electronic device during the time that the client computer is replaced with the second electronic device.

BACKGROUND

Voice over IP (VOIP) is a technology that permits the delivery of voicecommunications over networks that implement the Internet Protocol (IP),such as the Internet. A VOIP network includes a plurality of clientcomputers running software that supports VOIP. Voice connections can becreated between client computers. Other devices, for example landline ormobile phones, can be connected to the VOIP network using a gateway. Inaddition, a mobile phone that runs VOIP software can be directlyconnected to a VOIP network.

Because more than one device, for example a landline and a mobile phone,may be for the same user, a user may want to transfer a telephone callreceived on one user device to another user device. In order tofacilitate a telephone call transfer from one device to another devicefor the same user, a VOIP network may include one or more dedicatedserver computers, in some examples known as anchor servers, in which atelephone call is anchored for devices of the same user. An anchorserver provides a fixed connection to a remote party in which atelephone call to the remote party can be switched from one user deviceto another use device.

SUMMARY

One aspect relates to a method for transferring a telephone call from afirst electronic device to a second electronic device, the methodincluding: at the first electronic device, a connection for a telephonecall is established between the first electronic device and a thirdelectronic device. A request is sent to a server computer to transferthe telephone call from the first electronic device to the secondelectronic device. The first electronic device and the second electronicdevice have the same user. The request causes a connection to beestablished between the first electronic device and the secondelectronic device while maintaining the connection between the firstelectronic device and the third electronic device. The third electronicdevice is not put on hold while the connection between the firstelectronic device and the second electronic device is established. Aresponse is received from the server computer that the second electronicdevice accepted the telephone call. The first electronic device isreplaced with the second electronic device as a party in the telephonecall with the third electronic device. The continuity of the telephonecall is maintained at the third electronic device during the time thatthe first electronic device is replaced with the second electronicdevice. The telephone call is terminated at the first electronic device.

Another aspect includes a first electronic computing device that isconfigured to run a communications application. The first electroniccomputing device includes a computer readable storage medium, and aprocessing unit that executes computer readable instructions stored onthe computer readable storage medium. The processing unit creates a userinterface module that controls a user interface at the first electronicdevice, and a business logic module. The business logic moduleimplements communication functions for the communications application.The business logic module further includes a call manager that processesrequests to establish a telephone call connection from the firstelectronic computing device to a second electronic computing device, anda services manager that processes requests to transfer a telephone callestablished at the first electronic computing device to a mobile phone.The first electronic device and the mobile phone have the same user. Thetelephone call is transferred using a consultation transfer callprotocol that transfers the telephone call from the first electroniccomputing device to the mobile phone without putting the telephone callon hold. The service manager maintains continuity of the telephone callon the first electronic device while the telephone call is beingtransferred.

The details of one or more techniques are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages of these techniques will be apparent from the description,drawings, and claims.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example system for consultation call transfer acrossendpoints in a VOIP network.

FIG. 2 shows message flow in an example consultation call transfer usingthe system of FIG. 1.

FIG. 3 shows example modules of an example client computer of FIG. 1.

FIG. 4 shows an example user interface of an example client computer ofFIG. 1.

FIG. 5 shows example modules of an example business logic module of anexample client computer of FIG. 1.

FIG. 6 shows a flowchart of a method for using a consultation call totransfer a telephone call from a client computer to a second electronicdevice.

FIG. 7 shows example components of the client computer of FIG. 3.

DETAILED DESCRIPTION

The present application is directed to systems and methods for using aconsultation call to seamlessly transfer a telephone call from one userdevice to another device of the same user on a VOIP network.

In some examples, a call is transferred from a client computer to amobile phone of the same user or from a client computer to anotherdevice of the same user without making use of an anchor server. Theconsultation call allows the telephone call to be transferred withoutputting the call on hold while the call is being transferred. In thismanner, the telephone call is transferred seamlessly so that other userson devices that are connected to the client computer are unaware thatthe call is being transferred, and so that the continuity of the call ismaintained during the transfer process. In some examples, an anchorserver is not required, improving the efficiency of the call transferprocess and reducing capital equipment expenses for the VOIP network. Insome examples, a consultation call that allows a telephone call to betransferred from one device to another device of the same user is knownas a handoff.

A consultation call is a telephone call in which a person that wishes totransfer a call calls the person to whom the call is to be transferredto determine whether that person is willing to accept the call. If theperson to whom the call is to be transferred is willing to accept thecall, the person who wants to transfer the call typically presses atransfer button on his/her phone, and the call is then transferred. Theconsultation call can be initiated from a phone on the public switchedtelephone network (PSTN) or from a client computer running VOIP softwareon a VOIP network.

In a VOIP network, voice information is converted into packets ofinformation that are sent between nodes in the network. The nodestypically include client computers, server computers, routers andgateways. Each packet of information is sent as part of a message thatis sent between endpoint nodes in the network. For example, a clientcomputer that initiates a telephone call is one endpoint node and aclient computer that receives the call is a second endpoint node. Amobile phone to which a call is transferred is a third endpoint node. Inthis disclosure, a remote party is any endpoint other than the endpointthat initiates the transfer and the endpoint to which the call is to betransferred. The terms endpoint and endpoint node are usedinterchangeably.

Basic operations in a VOIP network are known as primitives. For example,initiating a telephone call is a primitive and a consultation call is aprimitive. Each primitive includes messages sent between nodes in thenetwork. A communication protocol provides rules for message transfer. Acommon communication protocol used in VOIP networks is the SessionInternet Protocol (SIP), described in RFCs 3261, 3515, 5589 and otherrelated RFCs. In examples, other communication protocols may be used. Inthe present disclosure, calls are transferred between endpoints in aseamless manner without putting the call on hold, ringing back anyremote parties, and/or using an anchor server.

FIG. 1 shows an example system 100 that supports consultation calltransfer across endpoints in a VOIP network. The example system 100includes client computers 102, 104, 106, communication server 108,gateway server 110, network 112, mobile phones 114, 116, PSTN 118 andwireless network 120.

The example client computers 102, 104, 106 have a software programinstalled that supports VOIP communication. One example software programis Microsoft Office Communicator from Microsoft Corporation of Redmond,Wash. The example communication server 108 provides the infrastructureto support VOIP, instant messaging, video conferencing and othercommunication services. An example communication server is MicrosoftOffice Communications Server 2007 from Microsoft Corporation of Redmond,Wash. The example network 112 is a packet switched network such as theInternet. The example PSTN 118 is a public switched telephone networkthat uses circuit switching.

The example gateway server 110 is a server computer provides aninterface between packet switched network 112 and circuit switched PSTN118. Example mobile phones 114, 116 are accessible to PSTN 118 viawireless network 120. More or fewer client computers, communicationservers, gateway servers and mobile phones can be used. Other types ofdevices, such as landline phones, can also be used.

The following describes an example consultation call transfer, asillustrated in FIG. 2. First, a telephone call is established betweentwo endpoints. For example a person at client computer 102, for exampleBob, calls a person at client computer 104, for example Alice, andestablishes a telephone call 202 between Bob and Alice. In this example,the telephone call is established between two VOIP nodes. However, inother examples, Bob may establish a telephone call from a landlinetelephone (not shown) connected to PSTN 118, from mobile phone 116 orfrom a client computer connected to a communication server other thatcommunication server 108. Other locations from which Bob may establishthe telephone call are possible. In other examples, Alice may initiatethe telephone call instead of Bob.

At some point in the example telephone call between Alice and Bob, Alicemay decide to transfer the telephone call to her mobile phone. Forexample, Alice may need to attend a meeting away from her office whilestill maintaining the telephone call. Using an user interface on clientcomputer 104, Alice requests that the telephone call be transferred toher mobile phone, for example mobile phone 114. In examples, the userinterface distinguishes between a handoff, in which a call is beingtransferred to a device of the same user and a traditional transfer inwhich a call is transferred to another user. Because Alice istransferring the call to herself, Alice presses a control on the userinterface that represents a handoff, for example a handoff button.

At this point, a consultation call is initiated between client computer104 and Alice's mobile phone 114. The pressing of the example handoffbutton on the user interface indicates to client computer 104 that theconsultation call is a handoff to Alice rather that a traditionaltransfer to another user. Therefore, client computer 104 keeps call 202active during the consultation call and does not put call 202 on holdduring the consultation call.

In the consultation call between client computer 104 and mobile phone114, a SIP Invite message 204 is sent from client computer 104 tocommunication server 108. The Invite message 204 includes an identifierfor Alice's mobile phone 114. The Invite message 204 may include one ormore parameters in the message header of Invite message 204. Forexample, one parameter may be a Skip RNL parameter that is used to skipa reverse lookup operation at the example communication server 108. Insome examples, use of the Skip RNL parameter prevents the consultationcall from being directed to any other of Alices's devices that may sharethe same phone number, for example a home phone. Another parameter maybe the reject-contact:MSGSERVER parameter, that in some examplesindicates that the consultation call should not be directed to voicemail on mobile phone 114.

When the example communication server 108 receives Invite message 204,the communication server 108 sends SIP Invite message 206 to examplegateway server 110. The Invite message 206 includes parameters from theInvite message 204, including the identifier for Alice's mobile phone114 and the Skip RNL parameter and the reject-contact:MSGSERVERparameter, if these parameters are included in Invite message 204. TheSIP Invite message 206 indicates to gateway server 110 that thetelephone call identified in SIP Invite message 206 is to be routed tomobile phone 114. The gateway server 110 then initiates a call toAlice's mobile phone 114. The call is sent to mobile phone 114 via PSTN118 and wireless network 120.

When the SIP Invite message 206 is received at mobile phone 114, a ringtone is sounded at mobile phone 114. When Alice accepts the call, SIP200 OK message 208 is sent from gateway server 110 to communicationserver 108 and SIP 200 OK message 210 is sent from communication server108 to client computer 104. Client computer 104 then sends SIP ACKmessage 212 to communication server 108 and communication server 108sends SIP ACK message 214 to gateway server 110. The SIP 200 OK messagesand the SIP ACK provide a handshake between client computer 104 andmobile phone 114. When gateway server 110 receives SIP ACK message 214,a connection 216 is established between mobile phone 114 and clientcomputer 104.

Because the connection 202 between Bob at client computer 102 and Aliceat client computer 104 is maintained during the transfer process, whenthe connection 216 is established between mobile phone 114 and clientcomputer 104, there are two at least two active connections—connection202 between Bob at client computer 102 and Alice at client computer 104and connection 216 between Alice at client computer 104 and mobile phone114.

When the connection 216 between client computer 104 and mobile phone 114is completed, client computer 104 sends SIP Refer message 218 tocommunication server 108 and communication server 108 sends SIP Refermessage 220 to gateway server 110. SIP Refer message 220 is a requestfor gateway server 110 to send an Invite with Replace message to Bob atclient computer 102 to replace client computer 104 with mobile phone 114in the telephone call with Bob.

When gateway server 110 receives Refer message 220, gateway server 110sends SIP 202 OK message 224 to communication server 108. In turn,communication server 108 sends SIP 202 OK message 224 to client computer104.

After gateway server 110 sends SIP 202 OK message 224 to communicationserver 108, gateway server 110 sends SIP Invite with Replace message 230to communication server 108. The SIP Invite with Replace message 230 isan SIP Invite message with a Replace parameter included in the message.SIP Invite with Replace message 230 also includes an identifier for theparty in the telephone call to be replaced (client computer 104) and anidentifier for the replacement party (mobile phone 114).

When communication server 108 receives SIP Invite with Replace message230, communication server 108 sends SIP Invite with Replace message 232to client computer 102. Client computer 102 then initiates an SIP OK/ACKhandshake with gateway computer 110 which comprises messages 234, 236,238 and 240. At the completion of the SIP OK/ACK handshake, a connection246 is established between Bob at client computer 102 and Alice atmobile phone 114. In addition, when client computer 102 receives SIP ACK240 from communication server 108, client computer 102 sends SIP BYEmessage 242 to client computer 108, and when client computer 108receives SIP BYE message 242, client computer 108 sends SIP BYE message244 to client computer 104 to end calls 202 and 216.

During the transfer and replacement process, the call is transferredfrom Alice's desktop connection at client computer 104 to Alice's mobilephone 114 without interruption of the call. From Alice's perspective,the call is transferred immediately when Alice accepts the consultationcall at mobile phone 114. In addition, Bob is not provided with anyindication that the call has been transferred to Alice's mobile phone114. Furthermore, the call is transferred without using an anchorserver.

The above example describes a seamless transfer of a telephone call fromclient computer 104 to mobile phone 114. However, other devices besidesa mobile phone can be used. For example, Alice may wish to transfer thetelephone call to her laptop computer, for example client computer 106,instead of to her mobile phone. When using a consultation call totransfer a call from client computer 104 to client computer 106, gatewayserver 110 is not needed because both client computer 104 and clientcomputer 106 are on a packet switched network controlled bycommunications server 108. Other examples are possible.

FIG. 3 shows example modules of client computer 102. The example modulesinclude a user interface module 302 and a business logic module 304. Theuser interface module 302 provides a user interface for the VOIPsoftware program installed on client computer 102.

FIG. 4 shows an example user interface 400 for client computer 102 thatis generated by the user interface module 302. The user interface 400includes an example user identification and status area 404 and anexample call status area 406. The user identification and status area404 identifies a user at the client computer, for example Alice, andprovides information about the user, such as job title, whether the useris currently in a call, etc. The call status area 406 provides a graphicindicating the status of a call. For example, if the user is in a call,a graphic of a handset may be displayed.

The user interface 400 also includes example buttons to activatingcommunication functions. Example functional buttons include transferbutton 408 which is used to initiate a call transfer to another user,handover button 410 which is used to transfer a call to a device of thesame user and example call button 412 which is used to initiate a call.Other buttons and additional functionality for the described buttons arepossible.

The user interface 400 also includes an example message area 414 whichlists status about a call and provides a history log of user actions.For example, the message area 414 may list all calls received, all callsinitiated, all calls transferred, etc. Other uses for the message area414 are possible.

The business logic module 304 provides the functionality for managingcalls and for providing additional services. FIG. 5 shows that thebusiness logic module includes an example call manager 502 and anexample services manager 504.

The call manager 502 establishes telephone call connections betweenclient computer 102 and other devices. The call manager 502 alsoprocesses requests for telephone call connections received at clientcomputer 102 from other devices. In examples, the call manager 502initiates and receives messages that are structured according to theSession Initiation Protocol (SIP) during the establishment of eachtelephone call connection.

The services manager 504 provides services including managing multiplecalls, processing standard requests to transfer calls and transferring atelephone call to a mobile phone of the same user via a consultationcall. Other services are possible. When providing services the servicesmanager 504 initiates and receives messages that are structuredaccording to SIP.

FIG. 6 shows an example flowchart of a method 600 for transferring atelephone call from a client computer to a second electronic device. Inmethod 600, the client computer and the second electronic device are ofthe same user. At operation 602, the client computer establishes atelephone call with a first electronic device. The client computer runsa software program that supports VOIP, such as Microsoft OfficeCommunicator. The first electronic device may be another client computerthat supports VOIP or a landline or mobile telephone connected via acircuit-switched telephone line. Other examples for the first electronicdevice are possible.

The telephone call is established over a network corresponding to thetype of first electronic device and where it is located. For example, ifthe first electronic device is a client computer at the same physicallocation as the client computer that establishes the telephone call, theconnection may be via a local area network. If the first electronicdevice is a client computer at a different physical location as theclient computer that establishes the telephone call, the connection maybe via the Internet. If the first electronic device is a desktoptelephone, the connection may be via a gateway server that provides aninterface to a PSTN. If the first electronic device is a mobiletelephone, the connection may be via a wireless network accessible to aPSTN.

At operation 604, the client computer sends a request to a servercomputer to transfer the telephone call to a second electronic device.The second electronic device belongs to the same user as the clientcomputer. An example request message is SIP Refer message 218. Theserver computer is typically a communication server that supports VOIPfunctionality, such as Microsoft Office Communications Server 2007. Thesecond electronic device is typically a mobile telephone but it can beany electronic device that supports voice communication. For example,the second electronic device may be a desktop computer or laptopcomputer that supports VOIP software. The transfer operation isinitiated by a user at the client computer pressing a handoff button onthe user interface of the client computer. The transfer operation isperformed using a consultation call to the second electronic device anddoes not require the use of an anchor server.

The request message to the server computer at operation 604, for exampleSIP Refer message 218, includes an identifier for the second electronicdevice and also includes an identifier for a third party to which thesecond electronic device is to connect. For example, the secondelectronic device is Alice's mobile phone 114 and the third party is Bobat client computer 102.

At operation 606, the client computer receives a response from theserver computer that the second electronic device has received the SIPRefer message. At operation 608, the telephone call is handed off fromthe client computer to the second electronic device. At operation 610,the telephone call is terminated at the client computer.

With reference to FIG. 7, example components of client computer 102 areshown. In example embodiments, the client computer is a computingdevice. The client computer 102 can include input/output devices, acentral processing unit (“CPU”), a data storage device, and a networkdevice. The other client computers 104, 106, the communication server108, and the gateway server 110 can be configured in a similar manner.

In a basic configuration, the client computer 102 typically includes atleast one processing unit 702 and system memory 704. Depending on theexact configuration and type of computing device, the system memory 704may be volatile (such as RAM), non-volatile (such as ROM, flash memory,etc.) or some combination of the two. System memory 704 typicallyincludes an operating system 706 suitable for controlling the operationof a networked personal computer, such as the WINDOWS® operating systemsfrom Microsoft Corporation of Redmond, Wash. or a server, such asWindows SharePoint Server 2007, also from Microsoft Corporation ofRedmond, Wash. The system memory 704 may also include one or moresoftware applications 708 and may include program data.

The client computer 102 may have additional features or functionality.For example, the client computer 102 may also include computer readablemedia. Computer readable media can include both computer readablestorage media and communication media.

Computer readable storage media is physical media, such as data storagedevices (removable and/or non-removable) including magnetic disks,optical disks, or tape. Such additional storage is illustrated in FIG. 7by removable storage 710 and non-removable storage 712. Computerreadable storage media may include volatile and nonvolatile, removableand non-removable media implemented in any method or technology forstorage of information, such as computer readable instructions, datastructures, program modules, or other data. Computer readable storagemedia can include, but is not limited to, RAM, ROM, EEPROM, flash memoryor other memory technology, CD-ROM, digital versatile disks (DVD) orother optical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or any other medium which canbe used to store the desired information and which can be accessed byclient computer 102. Any such computer readable storage media may bepart of device 102. Client computer 102 may also have input device(s)714 such as keyboard, mouse, pen, voice input device, touch inputdevice, etc. Output device(s) 716 such as a display, speakers, printer,etc. may also be included.

The client computer 102 may also contain communication connections 718that allow the device to communicate with other computing devices 720,such as over a network in a distributed computing environment, forexample, an intranet or the Internet. Communication connection 718 isone example of communication media. Communication media may typically beembodied by computer readable instructions, data structures, programmodules, or other data in a modulated data signal, such as a carrierwave or other transport mechanism, and includes any information deliverymedia. The term “modulated data signal” means a signal that has one ormore of its characteristics set or changed in such a manner as to encodeinformation in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media.

The various embodiments described above are provided by way ofillustration only and should not be construed to limiting. Variousmodifications and changes that may be made to the embodiments describedabove without departing from the true spirit and scope of thedisclosure.

1. A method for transferring a telephone call from a first electronicdevice to a second electronic device, the method comprising: at thefirst electronic device, establishing a connection for a telephone callbetween the first electronic device and a third electronic device;sending a request to a server computer to transfer the telephone callfrom the first electronic device to the second electronic device, thefirst electronic device and the second electronic device having the sameuser, the request initiating a consultation call to the secondelectronic device, the request causing a connection to be establishedbetween the first electronic device and the second electronic devicewhile maintaining the connection between the first electronic device andthe third electronic device, the third electronic device not being puton hold while the connection between the first electronic device and thesecond electronic device is established; receiving a response from theserver computer that the second electronic device has accepted thetelephone call; replacing the first electronic device with the secondelectronic device as a party in the telephone call with the thirdelectronic device, the continuity of the telephone call being maintainedat the third electronic device during the time that the first electronicdevice is replaced with the second electronic device; and terminatingthe telephone call at the first electronic device.
 2. The method ofclaim 1, wherein the first electronic device is a client computer. 3.The method of claim 1, wherein the second electronic device is a mobiletelephone.
 4. The method of claim 1, wherein the first electronic deviceruns software that supports a voice over Internet Protocol connection.5. The method of claim 4, wherein the software further supports theSession Initiation Protocol.
 6. The method of claim 1, wherein the firstelectronic device is a mobile telephone.
 7. The method of claim 6,wherein the mobile telephone runs software that supports a voice overInternet Protocol connection.
 8. The method of claim 1, wherein therequest to transfer the telephone call is initiated from a userinterface on the first electronic device.
 9. The method of claim 8,wherein the request to transfer the telephone call further comprisespressing a button on the user interface representing a handoff of thetelephone call, the handoff of the telephone call being a transfer ofthe telephone call to an electronic device of the same user as the firstelectronic device.
 10. The method of claim 9, wherein the request totransfer the transfer the telephone call is added to a history log onthe first electronic device.
 11. The method of claim 1, wherein therequest to transfer the transfer the telephone call is added to ahistory log on the first electronic device.
 12. The method of claim 1,wherein the telephone call between the first electronic device and thethird electronic device is initiated by the first electronic device. 13.The method of claim 1, wherein the telephone call between the firstelectronic device and the third electronic device is initiated by thethird electronic device.
 14. A first electronic computing device that isconfigured to run a communications application, the first electroniccomputing device comprising: a computer readable storage medium; and aprocessing unit that executes computer readable instructions stored onthe computer readable storage medium to create: a user interface modulethat controls a user interface at the first electronic device; and abusiness logic module, the business logic module implementingcommunication functions for the communications application, the businesslogic module further comprising: a call manager that processes requeststo establish a telephone call connection from the first electroniccomputing device to a second electronic computing device; and a servicesmanager that processes requests to transfer a telephone call establishedat the first electronic computing device to a mobile phone, the firstelectronic device and the mobile phone having the same user, thetelephone call being transferred using a consultation transfer callprotocol that transfers the telephone call from the first electroniccomputing device to the mobile phone without putting the telephone callon hold, the service manager maintaining continuity of the telephonecall on the first electronic device while the telephone call is beingtransferred.
 15. The first electronic computing device of claim 14,wherein the first electronic computing device is a client computer. 16.The first electronic computing device of claim 14, wherein the firstelectronic computing device is a mobile telephone.
 17. The firstelectronic computing device of claim 16, wherein the call manager andthe services manager process requests using the Session InitiationProtocol.
 18. The first electronic computing device of claim 16, whereinthe request to transfer the telephone call is initiated from the userinterface on the first electronic device.
 19. The first electroniccomputing device of claim 16, wherein the services manager maintains ahistory log of communication related actions at the first electronicdevice, the communication related actions including requests toestablish a telephone call, requests to transfer a telephone call andrequests to end a telephone call.
 20. A computer readable storage mediumcomprising instructions that, when executed by a processing unit of aclient computer, cause the processing unit to: establish a connectionfor a telephone call between the client computer and the firstelectronic device, the client computer displaying status informationabout the telephone call on a display device; send a request to a servercomputer to transfer the telephone call from the client computer to amobile phone, the request initiating a consultation call to the mobilephone, the client computer and the mobile phone having the same user,the request causing a connection to be established between the clientcomputer and the mobile phone while maintaining the connection betweenthe client computer and the first electronic device and without puttingthe first electronic device on hold while the connection is established;receive a response from the server computer that the mobile phone hasaccepted the telephone call; replace the client computer with the mobilephone as a party in the telephone call with the first electronic device,the continuity of the telephone call being maintained at the firstelectronic device during the time that the client computer is replacedwith the mobile phone; terminate the telephone call at the clientcomputer; and update a history log on the client computer, the historylog storing communication related actions including the request toestablish the telephone call, the transfer of the telephone call fromthe client computer to the mobile phone and the ending of the telephonecall at the client computer.